package com.ande.bridge.admin.conf;

import java.io.IOException;

import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;

import com.fasterxml.jackson.annotation.JsonInclude.Include;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializerProvider;

/**
 * @author chengzb
 * @date 2018年2月8日上午10:18:07
 * 〈返回json空值去掉null和""〉 
 */

@Configuration  
public class JacksonConfig  
{  
    @Bean  
    @Primary  
    @ConditionalOnMissingBean(ObjectMapper.class)  
    public ObjectMapper jacksonObjectMapper(Jackson2ObjectMapperBuilder builder)  
    {  
        ObjectMapper objectMapper = builder.createXmlMapper(false).build();  
  
        // 通过该方法对mapper对象进行设置，所有序列化的对象都将按改规则进行系列化  
        // Include.Include.ALWAYS 默认  
        // Include.NON_DEFAULT 属性为默认值不序列化  
        // Include.NON_EMPTY 属性为 空（""） 或者为 NULL 都不序列化，则返回的json是没有这个字段的。这样对移动端会更省流量  
        // Include.NON_NULL 属性为NULL 不序列化  
        objectMapper.setSerializationInclusion(Include.NON_EMPTY);  
  
        // 字段保留，将null值转为""  
        objectMapper.getSerializerProvider().setNullValueSerializer(new JsonSerializer<Object>()  
    {  
        @Override  
        public void serialize(Object o, JsonGenerator jsonGenerator,  
                              SerializerProvider serializerProvider)  
                throws IOException, JsonProcessingException  
        {  
            jsonGenerator.writeString("");  
        }  
    });  
        return objectMapper;  
    }  
}  
